Optolong L-eNhance Tri-Band Deep Sky Imaging Filter
 Optolong L-eNhance Tri-Band Deep Sky Imaging FilterOptolong L-eNhance Tri-Band Deep Sky Imaging Filter 

Optolong L-eNhance Tri-Band Deep Sky Imaging Filter

  (25 Reviews)
✓ 2 year warranty


23x in stock shipped 1-2 working days

About this product

Model:  opt_l-enhance_2
Part Number:  L-eNhance 2

Narrowband filter for one-shot colour / DSLR Imaging simultaneously captures H-alpha, H-beta and Oxygen III. 

The Optolong L-eNhance filter provides a practical solution to light pollution. 

Light pollution is a problem for all amateur astronomers and astrophotographers. The solutions can be expensive and might include purchasing a monochrome camera, several narrowband filters and a filter wheel. 

This tri-band filter for DSLR (digital SLR), colour CMOS and CCD cameras provides a more affordable, elegant, easier-to-use alternative. 

It effectively isolates the H-Alpha, H-Beta, and Oxygen III nebula emission lines and achieves a maximum transmission of up to 90%. 

The EOS-C Clip-in filter is compatible with all Canon EOS APS-C cameras except APS-S lenses.

IMPORTANT: Filters manufactured by Optolong are NOT designed for observing or photographing the Sun. DO NOT use Optolong filters to observe or photograph the Sun. If you do it will result in permanent eye damage! 


  • High transmission of H-Alpha, H-Beta and Oxygen III emission lines (avg. 90% or higher)
  • Use with colour DSLR, CMOS and CCD Cameras
  • 1.25" or 2" Mounted & EOS-C Clip-in Filter.
  • Supplied in a protective plastic case with EVA foam lining
  • More than 150 coating layers on B270 glass.
  • 1.85mm Thick Glass
  • Fine-optically polished on both sides - ensures accurate λ/4 wavefront and <30 seconds parallelism over the both surfaces
  • Ultrasonic wave cleaned substrate with purified water - Cleanup by 13-stage purified water tank to remove impurities and dust effectively
  • Ion source assisted coating— For durability and resistance to scratching, as well as stability on CWL (central wavelength)  - no deviation affected by temperature change
  • Stringent quality testing process - each filter is tested on a spectrophotometer and laser interferometer

Transmission Chart

White Line - Represents the transmission curve of the L-eNhance Filter.

The Major Emission Lines of Nebulae: H-α (656.3nm), H-β (486.1nm), OIII (495.9nm) and OIII (500.7nm)

The Major Emission Lines of Artificial Light Pollution: Hg / Mercury (435.8nm, 546.1nm, 577nm and 578.1nm), Na / Sodium (598nm, 589.6nm, 615.4nm and 616.1nm)

Sample Images

  • Imaging Target: Vela Supernova Remnant
  • Camera : CentralDS Astro A7s (cooled at -2C)
  • Lens : Canon EF 300mm f/4L (non-IS)
  • Filter: Optolong L-eNhance
  • ISO: 6400
  • Tracker: Star Adventurer
  • Autoguide: none
  • Exp time: 1min X 81frames
  • w Dark, Bias frames
  • Process with PI, PS CC
  • Offered by Optolong co-photographer Vincent Cheng

After a simple red structure transformation, the effect of SHO Hubble colour can also be simulated. Compared with the previous narrow band filters of Ha, SII and OIII, the L-eNhance filter is a good alternative. This multi-purpose approach is responsible for its success and popularity. 

  • Imaging Target:NGC 3372 Eta Carinae
  • Camera: QHY168C
  • Telescope: Pentax 100 SDUF II F/4
  • Filter: Optolong L-eNhance
  • Exposure:
    • Light Frames 15 x 240sec
    • Dark Frames 15 x 240sec
    • Bias Frames 50 x 0.001sec
    • Flat Frames 15 x 0.55sec
  • Software: SIRIL & Pixinsight 1.8.6
  • Offered by Optolong co-photographer Tommy Lim

What's in the box

  • L-eNhance Filter
  • Silver Cardboard Box
  • Plastic PP Box
  • High Pressure EVA case lining


Substrate: B270
Thickness: 1.85mm
Tpeak: T>90%
Blocking range: 300-1000nm
Blocking depth: light pollution  line blocking >99%
Surface quality: 60/40
Transmitted Wavefront RMS: λ/4
Parallelism (arcsec): 30s

Customer reviews

Average Rating (25 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Excellent initial results and no difficulty with the EOS clip
29 February 2024  | 

When I reviewed the Optolong L-Pro last year I expressed my disappointment with the fit of the EOS clip version (although I have no complaints about the performance of the L-Pro filter itself). Thankfully, Optolong has stuck with the design of EOS clip used by the other leading filter manufacturers (eg Astronomik) and this time the fit with the same Canon EOS 800D is faultless. Unlike the L-Pro version, the small 'arms' hold it in place and it does not drop out as soon as the camera is moved. I tried the L-eNhance with my 80ED refractor last week (we have Bortle 6 skies and halogen street lamps) and 2 hours total exposure on the Horsehead Nebula shows a notable improvement over the same exposure period using the L-Pro.

Rating (max 5):  
Great filter
09 September 2023  | 

This filter works great for reducing light pollution and moon glow in my images, just waiting for another clear night sky to use it again
It arrived next day, great service as always

Rating (max 5):  
Optolong l enhance
13 August 2023  | 

Arrived fast next day .as usual the English weather put a hold on testing
I've seen reports that the filter is loose I'm only using a 60d but it clips in very secure
Hope to update my review the sky's clear

Rating (max 5):  
L Enhance tri-band filter
14 July 2023  | 

Managed to get 2hours of data of the North American Nebula13/14 july and what a difference from the usual light polluted mush I've had to deal with in the past. A great addition to my imaging arsenal.

Rating (max 5):  
L-enhance filter
06 April 2023  | 

First of all thank you FirstLightOptics for the speedy delivery! i live in rural Washington state USA and i received in 6 days. Im using this filter with an 80mm f5.4 scope and zwo 533mc pro and the results are amazing even with full moon

Rating (max 5):  
Oolong l-enhance filter
19 January 2023  | 

Unfortunately the weather has not been kind of late and so I still have to try out in a proper session. I respect many other reviews of this item and Flo's customer service is, as always, second to none.

Rating (max 5):  
1.25" L-Enhance filter
04 January 2023  | 

I was a visual astronomer for years and I decided to try my hand at astrophotography. I live in bortle 5 and was having difficulty photographing emission nebula without the sky being blown out with light pollution. This filter is amazing and stopped me from throwing the towel in. I have captured numerous images which are detailed and clear. Definitely a game changer. Once I gain more experience with my OSC I will try my hand at other disciplines within astrophotography

Rating (max 5):  
Optolong L Enhance filter
29 December 2022  | 

I am using this with my Unistellar Evscope 2 telescope in a badly light polluted urban area.
The improvement is dramatic with better nebula definition and added colour to background star fields.

Rating (max 5):  
Works, but beware with Clip In!
10 December 2022  | 

Works great for the targets I’ve tried (even under full Moon conditions), but like Martin reviewed below, the clip in version with EOS cameras is NOT a clip in…frankly it’s a “sit in” filter.
I have a 77D and 800D and on both models, the filter simply “sits” in, it has no capability to “clip” as described. This is a major problem, because as the mount rotates, the filter then falls out of place, and in my case, actually cropped the top left/bottom right of my images!
Only solution I have is to sellotape it in…not what I’d expect for a £200 filter. As the other sizes aren’t compatible with my setup, I guess I’ll have to live with it. Didn’t get this problem with a svbony CLS filter.

Rating (max 5):  
Good filter start for beginners who want to try narrowband
08 September 2022  | 

You can already see the target at a single image. Great filter for bortle 4-5 areas.

Read all 25 customer reviews...


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